Influential factors for deterioration of freshness of vegetables include temperature, humidity, ambient gas, microorganisms, and light. Because respiration and transpiration occur on the surfaces of vegetables, in order to maintain the freshness of vegetables, it is necessary to reduce respiration and transpiration to a low level. Except for some vegetables susceptible chilling damage, respiration of most vegetables is reduced at a low temperature, and transpiration can be prevented in high humidity.
In recent years, household refrigerators are provided with a sealed dedicated container for the purpose of preserving vegetables, where vegetables are cooled to an appropriate temperature, and the humidity in the refrigerator is increased so as to keep transpiration from vegetables under control. Here, there is known a spray device for spraying mist as a unit to increase the humidity in the refrigerator.
As a refrigerator provided with spraying capability of this type, there is a refrigerator, in which a spray device humidifies the space in a vegetable compartment so as to keep transpiration from vegetables under control by spraying mist with an ultrasonic atomizing device when the vegetable compartment is at a low temperature (for example, see Patent Literature 1).
FIG. 6 is a vertical sectional view of the conventional refrigerator described in Patent Literature 1, and
FIG. 7 is a principal enlarged perspective view of an ultrasonic atomizing device provided in the vegetable compartment of the conventional refrigerator.
As shown in FIG. 6, a vegetable compartment 21 is provided in the lower portion of a body case 26 of a refrigerator body 20, and the front opening of the vegetable compartment 21 is designed to be closed by a drawer door 22, which may be drawn in a freely openable and closable manner. The vegetable compartment 21 is partitioned from the upper refrigerator compartment (not shown) by a partition plate 2. A fixing hanger 23 is fixed to the inner surface of the drawer door 22, and a vegetable container 1 which stores food such as vegetables is mounted on the fixing hanger 23. The top opening of the vegetable container 1 is sealed by a lid 3. The inside of the vegetable container 1 is provided with a thaw compartment 4, and the rear surface of the thaw compartment 4 is provided with an ultrasonic atomizing device 5.
As shown in FIG. 7, the ultrasonic atomizing device 5 includes a mist diffuser 6, a water storage container 7, a humidity sensor 8, and a hose receiver 9. The water storage container 7 is connected to a defrost water hose 10 via the hose receiver 9. A portion of the defrost water hose 10 is provided with a cleaning filter 11 for cleaning defrost water.
Hereinafter, the operation of the refrigerator as configured in this manner is described.
First, cooling air cooled by a heat exchange cooler (not shown) circulates along the outer surface of the vegetable container 1 and a lid 3 so that the vegetable container 1 is cooled, and thus the food stored therein is cooled. The defrost water generated from the heat exchange cooler when the refrigerator is in operation is cleaned by the cleaning filter 11 as passing through the defrost water hose 10, and is supplied to the water storage container 7 of the ultrasonic atomizing device 5.
Next, when the humidity in the refrigerator is detected to be 90% or less by the humidity sensor 8, the ultrasonic atomizing device 5 starts to humidify the inside of the refrigerator and controls the humidity to an appropriate level in order to keep the vegetables in the vegetable container 1 fresh. On the other hand, when the humidity in the refrigerator is detected to be 90% or more by the humidity sensor 8, the ultrasonic atomizing device 5 stops excessive humidification. Consequently, the inside of the vegetable compartment 21 is kept in the most appropriate humidity state by the ultrasonic atomizing device 5.